1. Field of the Disclosure
The present disclosure relates to compositions comprising 2,3,3,3-tetrafluoropropene (HFO-1234yf) or 1,3,3,3-tetrafluoropropene (trans-HFO-1234ze) or a mixture thereof; difluoromethane (HFC-32); and 1,1, difluoroethane (HFC-152a), 3,3,3-trifluoropropene (HFO-1243zf) or mixture thereof.
The compositions of the present invention are useful in processes for producing cooling or heat, as heat transfer fluids, foam blowing agents, aerosol propellants, and as power cycle working fluids.
2. Description of Related Art
The refrigeration industry has been working for the past few decades to find replacement refrigerants for the ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). CFCs and the HCFCs are being phased out as a result of the Montreal Protocol. The solution for most refrigerant producers has been the commercialization of hydrofluorocarbon (HFC) refrigerants. For example, the new HFC refrigerants, HFC-134a being the most widely used at this time, have zero ozone depletion potential and thus are not affected by the current regulatory phase out as a result of the Montreal Protocol.
However, further environmental regulations may ultimately cause global phase out of certain HFC refrigerants. Currently, the industry faces regulations relating to global warming potential (GWP) for refrigerants used in mobile air-conditioning. Should the regulations be more broadly applied in the future, for instance for stationary air conditioning and refrigeration systems, an even greater need will be felt for refrigerants that can be used in all areas of the refrigeration and air-conditioning industry. Uncertainty as to the ultimate regulatory requirements relative to GWP, have forced the industry to consider multiple candidate compounds and mixtures.
Currently proposed replacement refrigerants for HFC refrigerants and refrigerant blends include, for example, pure hydrocarbons such as butane or propane, or “natural” refrigerants such as CO2. However, these suggested replacements have problems including toxicity, flammability, low energy efficiency, or require major equipment design modifications. Similarly, new replacements are being proposed also for R-22, R-134a, R-404A, and R-407C among others. Uncertainty as to what regulatory requirements relative to GWP will ultimately be adopted have forced the industry to consider multiple candidate compounds and mixtures that balance the need for low GWP, non-flammability or low flammability, and existing system performance parameters.